Apparatus for ascertaining the acceleration due to gravity



No. 751,517; Q PATBNTBD FEB. -9, 1904. P. Guw. KELLER.

APPARATUS FOR A SGERT'AINING THE ACCELERATION DUE TO GRAVITY.

APPLICATION 11.21) mu. 5. 1903. I I0 10mm. 2 sums-31mm 1.

. i ii -m ERS co. PHDTO-LITHO., WASHINGTON u c No. 751,517. I PATENTEDFEB. 9, 1904. P. G; W. KELLER.

APPARATUS FOR ASOBRTA'INING THE ACCELERATION DUE TO GRAVITY.

APPLICATION FILED MAR. 5. 190a.

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Patented. February 9, 1904.

PAUL'G. W. KELLER, OF MANITOWO C WISCONSIN.

APPARATUS FOR ASCERTAINING THE ACCELERATION DUE TO GRAVITY.

SPECIFICATION forming part of Letters Patent No. 751,517, datedFebruary- 9, 19 04. 7

Application filed March 5, 1903. Serial 110. 146,364. (n model.)

To all whom it may concern:

Be it known that IQPAUL Gr. W. KELLER, a citizen of the United States,residing at Manitowoc, in the county of Manitowoc and State of 5Wisconsin, have invented certain new and useful Improvements inApparatus for Ascertaining the Acceleration Due to Gravity, of which thefollowing is a specification.

My invention relates to apparatus for dem-. I onstrating the laws ofacceleration and for finding the value of gravity.

The object of myinvention is theprovision of a scientific apparatus forenabling the computation of acceleration of a traveling body I upon anincline, to find the value'of the inclination from the horizontal of thetrack upon which the body travels, and from these the value of gravityfor a given place; and the invention consists in the combination and 2arrangements of parts, as hereinafter described and claimed.

In the accompanying drawings, Figure 1 is an elevation of my apparatusas a whole. Fig. 2 is a section on line 2 2, Fig. 3-. Fig. 3 is an '25end view of the traveling carriage. Figs. 4, 5, and 6 are views of thefront and'sides, respectively, of the adjustable track-terminalholdingblock; and Figs. 7 and Sam side and front elevations, partly in section,of thepen- 3 'dulum and body used in my apparatus.

1n the drawings, the base-boards (designated as 1 1) are shown attachedby screws or otherwise to suitable bases, as the side walls of a room.The base-boards are connected by a pair of wires 2 2', which forconvenience may be called a track. The lower one of the tracks 2 has amilled surface on its under side for a purpose to be describedhereinafter. Traveling upon the rails is a carriage,

4 as 3, provided with a suitable number of up- 5 per and lowersupporting and guiding wheels, in this instance four being used. Thecarriage proper consists of two side plates connected by pins 4:, asshown, or other suitable connecting means may be employed. Interposedbetween the walls of the carriage are the four supporting-wheels, andalso an electromagnet 5 may be attached in any suitable man ner to theside walls.

5 At the left in Fig. 1 the terminal of the tracks 2 2"consists of anadjustable block 6,

provided with tension-screws 4:5 and 46, having rings, which may besuitably insulated from the tracks by, the use of anon-conductinglining, such as rubber, inside the rings. These rings 6' 6 are forattachment of the track-wires. The adjustable block 6 is mounted in agrooved or hollow supporting-piece 7,- having brackets 8 8, which may befastened to the base-board's 1. The tracks or wires being rigidlyfastened to the base-board 1 at the right of Fig. 1, they may beadjusted within limits-to any inclination by means of the set-screws 9,acting upon the adjustable block 6, as shown in dotted lines, Fig. 1 ina manner which will be obvious from the drawings. A modification of theadjusting mechanism, which is the construction I prefer for attaining adesired inclination of the wires, is shown in Figs. 4:, 5, and 6,wherein one edge of the adjusting-block 6 is provided with a milled ortoothed surface 10, in which mesh the teeth of a wheel .11, suitablymounted in.

bearings upon the supporting-bracket 7 and by means of the wheel-head,12 said toothed wheel 11 may be turned, thus raising or lowering theadjustable block 6, and with it the suspended wires or tracks 2 2.

The operating mechanism of my apparatus consists of a pendulum 13,suitably mounted upon the base-board 1 and provided with a cap 14,whichI call the starting-cap. Said cap may be thrown into or out ofoperating position by means of the cam-disk 15, as will be understood,and when in position during the vibration of the pendulum is adapted tocontact with the point 16 of pivoted starting-lever 17. Said lever 17has a hook 18 at itsend, which engages the pin 1' of the travelingcarriage 3 and normally holds said carriage at the starting-point. A pin19 maybe located on the base-board 1 to limit the movement of the lever17 A pawl 20, having a suitable weight thereon, is pivoted to thestarting-lever 17 and said pawl engages the teeth of a 95 ratchet-wheel21, mounted to rotate upon said base-board 1. A dog 22 may be providedto prevent backward movement of the ratchet;

To further secure the operation of my apparatus, Iuse the electricalconnections shown I00 and which may be described as follows: Theterminals 23 and 24; of the right-hand end of the metallic wires ortracks 2 2 may also be bindingposts having wires electrically connectedwith said tracks. At least two of the wheels, as 25 25, of the travelingcarriage 3 are of metal and have conductors from their respective axlesconnected to the magnet 5, located in said carriage. The circuit iscompleted from the other side of the bindingposts 23 and 24 and throughthe battery, conductor 27 leading to the starting-lever 17, through saidlever, pawl 20, wheel 21, elevated portion 28 of wheel 21, brush 29, andconduc-' tor 30, thence to the binding-post 24:. If it is desired to usethe pendulum as a secondspendulum, I locate a key 31 and sounder 32 onthe base-board and connect by conductor to the dog 22, insuring a clickat intervals of a second as the dog 22 trips from cog to cog of thewheel 21, thus breaking the current, which breaks are registered by aclick on the sounder.

The armature 34 of the magnet 5 is provided with a bar or rod 35. Saidrod or bar passes through holes in the plates of the magnet, beingprevented from dropping entirely through said openings by ahead-piece36. At the lower end of the rod or bar 36 I provide a transverseopening, through which opening passes the track 2.

A block or plate 38 is formed integrally at the extreme end of rod 35,having its upper surface, a part of which constitutes a face of theopening 37, milled to correspond with the milled under surface of thetrack 2. This plate or block 38 is adapted to engage with track 2 andthus stop the course of the carriage 3 after it has been started, in amanner to be described. A needle or pointer 39 of any suitable designmay be attached to the carriage 3 and is adapted during the travel ofsaid carriage to indicate upon a predetermined scale, as 40, thedistance traveled by the carrlage.

The preferable length of the track as I have used in practicaldemonstrations is about fifteen or twenty feet; but this distance can bevaried according to existing conditions. The scale 40 should preferablybe graded in centimeters, as indicated, and is marked off by arcs havingtheir centers at the point of convergence of the horizontal line of thescale and the inclined line thereof, which will enable a reading of thescale no matter what the inclination of the track might be.

By means of the pendulum, starting-lever, and ratchet connections thecarriage 3 is released when the pendulum reaches its vertical positionduring oscillation and after the apparatus has been set in gear byturning the eccentric disk 15, and if the wheel 21 is so set that thecog opposite a, Fig. 1, or any other tooth of the wheel, accordingly asthe distance traveled during one, two, or three seconds or othersuitable unit of time is required, is engaging the ratchet the carriagewill be stopped by means of the electrical connections at the end of thefirst second, as indicated by the needle 39 in Fig. 1, for as thependulum returns it throws the elevated portion 28 of wheel 21 intocontact with brush 29. This completes the circuit through theelectromagnet 5 inthe carriage 3, and the armature 34c draws thestop-block 38 upon or against the milled under surface of the track 2',thus stopping the movement of the carriage. The pointer 39 indicates thedistance traveled by the carriage directly by reading to scale. Thisenables the computation of the value of acceleration for the givenincline, as will be readily recognized by persons skilled in this art.

By means of the adjustable block 6 the amount of inclination from thehorizontal can be read from the Vernier-micrometer, as seen in Fig. 4.Knowing the length of the track as shown by the scale, the value ofgravity is found at once from the formula al+d= 9, where (Z is theamount of inclination of the track, Z the length of the track, a theacceleration determined for the inclination d, and g the value ofgravity for the given place.

Having thus fully described my invention, what I claim, and desire tosecure by Letters Patent, is-

1. The combination of a plurality of tracks, adjustable as to theirinclination, with a traveling carriage thereon, and means for startingsaid carriage, and for stopping it at the end of a predeterminedinterval of time.

2. In an apparatus as described, a plurality of tracks, a travelingcarriage thereon, a bracket at one end and a track terminal-blockadjutable in said bracket as to height by means of a ratchet and wheeland a suitable support at the other end of said tracks, substantially asdescribed.

3. An apparatus as described consisting of a plurality of tracks, acarriage traveling thereon, provided with a stop-block, and anelectromagnet, said stop-block adapted to engage with said track ortracks when operated by the armature of said electromagnet.

4. A traveling carriage provided with suitable wheels and axles, atrackway, an electromagnet, a stop-block operated by said electromagnetand adapted to engage the trackway to stop the travel of the carriageupon which it is located, and suitable electrical connections to saidmagnet, combined substantially as described.

5. A traveling carriage as described, a trackway having a milledsurface, an electromagnet, a rod provided with a milled portionconnected to the armature of the magnet, and electrical connections tosaid magnet whereby said rod is operated by the movement of saidarmature to make engagement between the milled portions of thestop-block and the trackway.

and electrical connections, whereby the movement of the oscillatingmechanism causesa movement of the pawl and ratchet which in turnoperates a, sounder located within the electrical connections.

In testimony whereof I aflix my signature in if presence of twowitnesses.

PAUL KELLER.

Witnesses: I f

HELEN F. UARNIGHT, ELLA E. HARRINGTON.

